Experimental: send far blocks as non reliable

Squashed commit of the following:

commit 6b3062c9b06828119d1c402306dbda2e01da342c
Merge: f8de09d 446ea37
Author: proller <proller@github.com>
Date:   Sun Dec 22 04:23:30 2013 +0400

    Merge remote-tracking branch 'upstream/master' into lag

commit f8de09d0b2f7366c759380b275556124006ad17b
Author: proller <proller@github.com>
Date:   Sun Dec 22 03:45:23 2013 +0400

    far non reliable blocks

commit 0e90dc44701428ffb2837c1f8799e8f828b45b7e
Author: proller <proller@github.com>
Date:   Fri Dec 20 02:35:16 2013 +0400

    Experimental: send far blocks as non reliable

commit b5fff347151966ecb471ff837e3f9ed56eb0b317
Author: proller <proller@github.com>
Date:   Fri Dec 20 01:07:12 2013 +0400

    tune

commit c6b13e71bb925409091004d2abea1628fc80d8ef
Author: proller <proller@github.com>
Date:   Fri Dec 20 00:23:17 2013 +0400

    still tuning

commit 4ed7aaa0abe6b6b5c4d4d0adf2276b4863c0900e
Author: proller <proller@github.com>
Date:   Fri Dec 20 00:10:25 2013 +0400

    Tuning for slow mobile conections

commit 9e7bfcc3c8269552cb0b4cbe3aeab596dcb9a18c
Author: proller <proller@github.com>
Date:   Thu Dec 19 23:31:58 2013 +0400

    Connecction tune